Examining firearm-related deaths in Mexico, 2015–2022

Background Globally, Mexico is one of six countries with the highest level of firearm mortality. While previous studies have examined firearm mortality in Mexico before 2015, increases in violence since then highlight the need for an updated analysis. In this study, we examined changes in firearm-related deaths in Mexico from 2015 to 2022 and described these deaths by key demographic groups, incident location, and state of occurrence. Data came from Mexico’s Instituto Nacional de Estadistica y Geografia (INEGI), a federal agency that collects and reports national population data. We used descriptive statistics to analyze rates, proportions, and percentage changes in firearm mortality, and we displayed temporal trends using time plots and special trends using maps. Results Firearm deaths increased in Mexico from 2015 to 2018 but slightly decreased from 2018 to 2022. Homicides presented the highest increase and the highest proportion of firearm-related deaths from 2015 to 2022. Victims were primarily males but rates among women increased at a higher proportion (99.5% vs 53.5%). One third of victims were 20–29y but rates among children and adolescents (10–9y) increased at a higher proportion. Most firearm-related deaths occurred in streets or public spaces but the percentage of incidents occurring in households have increased. State-level rates and percentage changes varied significantly. States with higher rates of firearm mortality coincide with those involving conflict among organized criminal organizations. Conclusion Firearm mortality in Mexico is a major public health burden. The epidemiology of firearm-related deaths in Mexico varies by intent, demographics, location, and states. To mitigate this challenge, multiple solutions are required.


Introduction
Previous studies have documented increases in firearm mortality in Mexico from 1990 to 2015 (Dare et al. 2019).Reports from nonprofit organizations and news outlets indicate further increases since 2015, (particularly firearm homicides associated with organized crime) (Calderon et al. 2020), but comprehensive characterization of those trends is lacking.Organized criminal groups continue to operate in Mexico and roughly 213 k firearms are trafficked from the US every year (McDougal et al. 2014).In this regard, further increases in firearm mortality would threaten the future economy and health of Mexico (Peters et al. 2020;Aburto et al. 2016), and yet the lack of precise epidemiological information limits the ability to address this growing national problem with evidencebased programs and policies.In this analysis, we document changes in firearm-related deaths in Mexico from 2015 to 2022 and describe these deaths by key demographic groups (e.g., sex, age, and urbanicity), incident location (e.g., households or public spaces) and states where they occurred.

Methods
Data on causes of death were collected from Mexico's Instituto Nacional de Estadistica y Geografia (INEGI), a national vital statistic database that has previously been used to examine firearm mortality in Mexico (Dare et al. 2019; Instituto Nacional de Estadística y Geograf ía 2023a).INEGI collects annual mortality data and provides information on year of occurrence (Instituto Nacional de Estadística y Geograf ía 2023b).We merged datasets from 2015 to 2022.We excluded deaths that occurred/registered before 2015 and those where year of occurrence was unknown (n = 432), as well as deaths that occurred outside of Mexico (n = 2).
We used descriptive statistics to examine pooled 2015-2022 rates, annual rates for 2015 and 2022 separately, as well as percentage changes (in rates) from 2015 to 2022 across categories of intent, sex, age groups, and state of occurrence.To obtain rates, we used population estimates (by year, sex, age group, and state) provided by Mexico's Consejo Nacional de Población (CONAPO) (Consejo Nacional de Población 2024).We also examined the percentage of firearm related deaths within categories defined by urbanicity, location, intent, and demographics.We displayed these percentages for 2015, 2022, and the total pooled 2015-2022 period.

Results
We examined 188,397 firearm-related deaths in Mexico from 2015 to 2022.Rates of firearm-related deaths increased by 88.2% from 2015 to 2018 and decreased by 16.7% from 2018 to 2022 (Fig. 1).Homicide accounted for 92.2% of firearm deaths (Table 1) during this period and experienced the highest percentage increase (62.7%) from 2015 (10.37 per 100 k) to 2022 (16.87 per 100 k).Rates of undetermined firearm-related deaths and unintentional shootings also increased during this period (Table 1), while firearm suicide decreased by 23.4% (from 0.47 per 100 k in 2015 to 0.36 per 100 k in 2022).
Males represented 91.2% of firearm-related deaths (Table 1).However, increases from 2015 to 2022 were larger among women than men (99.5% vs 53.3%).Sex of decedent was missing in < 1% of deaths.Individuals ages 20-29y represented close to one third of firearm-related victims (31.9%) but rates were higher among individuals ages 30-39y (35.66 per 100 k).Across age groups, the largest percentage rate increase (67.6%) from 2015 to 2022 was among those aged 10-19y (from 5.16 to 8.65 per 100 k).Age of decedent was missing in 3.7% of deaths.
The percent of firearm deaths occurring in urban areas increased from 76.8% in 2015 to 86.8% in 2022 (Table 2).Across all intents, most deaths occurred in urban areas (Table 2).However, roughly one out of every four firearm suicides (27.2%) occurred in rural areas, the highest proportion across all intents.By age group, 23.1% of firearm deaths among those ages 0 to 9 and over 25.0% of those 60-69y as well as 70+ years of age occurred in rural areas (Table 3).Urbanicity was missing in 8.4% of deaths.
When examining incident location (Table 2), 67.3% of deaths occurred in the street or in public spaces.However, the percentage of incidents occurring in households increased from 14.0% in 2015 to 17.7% in 2022.While homicides occurred mainly in streets and public spaces (69.2%), firearm suicides occurred primarily in households (73.3%).The proportion of firearm-related deaths among women that occurred in households (27.0%) is larger than the percentage among men (13.8%).More than 64.0% of firearm-related deaths among those age 10-19y, 20-29y, 30-39y, and 40-49y occurred in streets or public spaces (Table 3), while the proportion of incidents occurring in households was higher among victims 0-9 years of age (35.5%) and among those older than 69 years of age (49.2%).Incident location was missing in 17.3% of deaths.
The five states with the highest rates of firearm mortality per 100 k from 2015 to 2022 (Fig. 2A) were Colima (66.91),Baja California (48.23),Zacatecas (44.35),Chihuahua (43.51),and Guanajuato (42.87).The five states with the lowest rates of firearm mortality per 100 k were Yucatan (0.83), Aguascalientes (3.45), Coahuila (4.05), Queretaro (4.97), and Campeche (4.98).Most states experienced significant shifts in rates of firearm mortality from 2015 to 2022, however, these changes were not homogenous across states (Fig. 2B).For example, five states experienced a decline of more than 50.0%(e.g., Baja California Sur decreased by 84.7%) while seven    The state where the death occurred was missing in < 2% of incidents.Percentage changes in the state of Yucatan are based on counts of < 30.

Interpret with caution
Our results suggest demographic-and location-specific challenges around firearm mortality that require complementary approaches.Rates among women have increased at a higher proportion than men, coinciding with increases in femicides in Mexico in recent years (Hernandez Gress et al. 2023).While firearm-related deaths among women occurred more frequently in the street/ public spaces, our results indicate that one out of four firearm-related deaths among women occur in a household, suggesting homicides related to domestic violence.Similarly, individuals aged 10-19y presented the highest relative rate increase from 2015 to 2022.As firearms have become a major cause of death for children and adolescents in Mexico (Castilla Peon et al. 2023), focusing on curbing this trend is critical.Also, as 35.5% of firearm deaths among children (0 to 9) occur in households, it is important to focus on reducing access to firearms among children as well as reducing firearm availability where there is domestic violence.Moreover, while rates of firearm suicides and unintentional shootings are not as high as firearm homicides, they occur more frequently within households.At the same time, close to 27.2% of firearm suicides occur in rural areas despite such areas representing 21.0% of the population (Instituto Nacional de Estadística y Geograf ía 2024).Policymakers could examine and potentially replicate US policies to limit access to firearm for domestic abusers, children, adolescents, and those at risk of suicide.Suicide prevention policies could include the adoption of extreme risk protection orders, a policy that has been associated with a reduction in firearm suicides in US states (Kivisto and Lee 2018).Moreover, while firearm laws are regulated at a federal level, future studies could evaluate the adequate implementation of Mexico's firearm laws.
In addition, while firearm mortality increases were seen in official data following the start of the COVID-19 pandemic period (2020-2022) in the US (Sun et al. 2022), this did not occurred in Mexico.Rates in Mexico presented decreases of 1.0% from 2019 to 2020 and 6.2% from 2020 to 2021.These changes followed a similar decrease of 1.0% from 2018 to 2019 (pre pandemic).Nonetheless, within categories of intent, trends in rates of death by unintentional shootings increased 50% from 2019 to 2020 (0.44 to 0.66 per 100 K) and maintained similar levels during 2021 (0.60 per 100 k).Future studies should examine associations between factors arising from the COVID-19 pandemic and firearm mortality.
Findings from this analysis have implications beyond Mexico.US federal agencies have reported that many firearms recovered in Mexico and traced by the Bureau of Alcohol Tobacco Firearm and Explosives (ATF) originate in the US (Bureau of Alcohol Tobacco Firearms and Explosives (ATF) 2022).Researchers have also reported a strong association between US firearm markets (manufacturing and imports) and rates of firearm homicides in Mexico (Perez Esparza et al. 2020;Weigend Vargas et al. 2024).As studies have documented increases in firearm-mortality in the US after 2014 and have reported firearms as the number one cause of death among children and adolescents (Goldstick et al. 2022), efforts to address these challenges should also consider firearm mortality in countries that are major recipients of legal and illegal US firearms.Additionally, bilateral agreements between Mexico and the US to reduce firearms trafficking and increase oversight of firearm exports should be considered.
There are limitations to our study.Our analysis is based on mortality that has been reported to INEGI.However, as presented in this study, there is missing data across numerous categories, including information on state and year of occurrence as well as incident location.This highlights the need for more comprehensive and timely data collection.Potentially, Mexico could replicate US efforts in creating the National Violent Death Reporting System (NVDRS) (Centers for Disease Control and Prevention 2024), starting with pilot programs in selected states or cities.Despite these limitations, INEGI is recognized as a reliable source in reporting mortality in Mexico and has been used in previous studies examining firearm mortality (Castilla Peon et al. 2023).Another limitation is that we are not characterizing increases in nonfatal shootings.As studies have documented that nonfatal shootings in Mexico are more likely to occur than fatal shootings (Weigend Vargas and Perez 2022), future research should focus on conducting epidemiological studies to describe this challenge.Finally, state rates are based on resident population, which may not perfectly proxy the susceptible population within a given year.
Firearm mortality in Mexico is a major public health burden.The epidemiology of firearm-related deaths in Mexico varies by intent, demographics, and states.To mitigate this challenge, multiple solutions are required.These include programs and policies to mitigate violence associated with organized criminal groups, including efforts to reduce firearms trafficking from the US.Federal and state policies should also consider complementary public health approaches, including better data compilation and the potential adaptation of policies and programs that have been effective at reducing firearm mortality in other countries.

Fig. 2 A
Fig. 2 A Firearm mortality rates across Mexican states, 2015-2022, B Percentage change in rates of firearm mortality from 2018 to 2022 by state.The state where the death occurred was missing in < 2% of incidents.Percentage changes in the state of Yucatan are based on counts of < 30.Interpret with caution

Table 1
Rates of firearm deaths, percentage increases in rates, and the proportion of firearm deaths by intent, sex, and age groups, 2015-2022 There were few observations where sex (< 1%) and age (< 4%) were missing.Hence, the proportion of firearm deaths among these categories (5th column) are based on specified data (excluding missing data).Percentage changes (4th column) are based on rates rounded to the hundredth place (Mexico 2024).Additionally, our results indicate that rates of firearm-deaths varied over time.This suggests the need to rely on the most recent epidemiological data to dictate public health priorities and response activities.

Table 2
Percentage of firearm deaths (across years, intent, and sex) by urbanicity and location, 2015-2022 Observations for urbanicity (8.4%) and for location (17.3%) were missing.To estimate percentages for each category, missing data was excluded

Table 3
Percentage of firearm deaths (across age groups) by urbanicity and location, 2015-2022